An extended architecture built upon the double-Dawson-type polyoxoanion.

An unprecedented extended architecture, Na(8)H(2)L(H(2)enMe)(4){Mn(H(2)O)(2)[(W(4)Mn(4)O(12))(P(2)W(14)O(54))(2)]}.17H(2)O, (, Na(8)H(2)L(H(2)enMe)(4)[].17H(2)O, enMe = 1,2-diaminopropane) constructed from double-Dawson type polyoxoanions (DDTP) has been successfully synthesized under hydrothermal conditions. Single-crystal X-ray diffraction analysis is carried out on , which crystallizes in the monoclinic system, space group C2/c, a = 43.974(9) A, b = 13.869(3) A, c = 28.385(6) A, beta = 71.34(3) degrees, V = 15308(5) A(3), and Z = 4. Polyoxoanion exhibits a double-Dawson-type structure which is composed of two tetra-substituted-Dawson anions. These DDTPs are further connected by Mn(2+) linkers into the one-dimensional (1D) inorganic chains. To the best of our knowledge, it is the first example of an inorganic chain constructed from DDTPs. The 1D inorganic chains are further connected into a 3D supramolecular structure via hydrogen bonding interactions between 1,2-enMe molecules, H(2)L ligands and the DDTP. Electrocatalytic studies indicate that compound displays electrocatalytic activity toward the reduction of nitrite.